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From: Peter Zijlstra <peterz@infradead.org>
To: umgwanakikbuti@gmail.com, mingo@elte.hu
Cc: ktkhai@parallels.com, rostedt@goodmis.org, tglx@linutronix.de,
	juri.lelli@gmail.com, pang.xunlei@linaro.org, oleg@redhat.com,
	wanpeng.li@linux.intel.com, linux-kernel@vger.kernel.org,
	peterz@infradead.org
Subject: [PATCH 07/18] sched,dl: Convert switched_{from,to}_dl() / prio_changed_dl() to balance callbacks
Date: Thu, 11 Jun 2015 14:46:43 +0200	[thread overview]
Message-ID: <20150611124742.968262663@infradead.org> (raw)
In-Reply-To: 20150611124636.448700267@infradead.org

[-- Attachment #1: peterz-sched-post_schedule-5.patch --]
[-- Type: text/plain, Size: 3223 bytes --]

Remove the direct {push,pull} balancing operations from
switched_{from,to}_dl() / prio_changed_dl() and use the balance
callback queue.

Again, err on the side of too many reschedules; since too few is a
hard bug while too many is just annoying.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/deadline.c |   45 ++++++++++++++++++++++++---------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -213,16 +213,23 @@ static inline bool need_pull_dl_task(str
 	return dl_task(prev);
 }
 
-static DEFINE_PER_CPU(struct callback_head, dl_balance_head);
+static DEFINE_PER_CPU(struct callback_head, dl_push_head);
+static DEFINE_PER_CPU(struct callback_head, dl_pull_head);
 
 static void push_dl_tasks(struct rq *);
+static void pull_dl_task(struct rq *);
 
 static inline void queue_push_tasks(struct rq *rq)
 {
 	if (!has_pushable_dl_tasks(rq))
 		return;
 
-	queue_balance_callback(rq, &per_cpu(dl_balance_head, rq->cpu), push_dl_tasks);
+	queue_balance_callback(rq, &per_cpu(dl_push_head, rq->cpu), push_dl_tasks);
+}
+
+static inline void queue_pull_task(struct rq *rq)
+{
+	queue_balance_callback(rq, &per_cpu(dl_pull_head, rq->cpu), pull_dl_task);
 }
 
 static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq);
@@ -305,6 +312,10 @@ static inline void pull_dl_task(struct r
 static inline void queue_push_tasks(struct rq *rq)
 {
 }
+
+static inline void queue_pull_task(struct rq *rq)
+{
+}
 #endif /* CONFIG_SMP */
 
 static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags);
@@ -1048,8 +1059,6 @@ static void check_preempt_equal_dl(struc
 	resched_curr(rq);
 }
 
-static void pull_dl_task(struct rq *this_rq);
-
 #endif /* CONFIG_SMP */
 
 /*
@@ -1713,7 +1722,7 @@ static void switched_from_dl(struct rq *
 	if (!task_on_rq_queued(p) || rq->dl.dl_nr_running)
 		return;
 
-	pull_dl_task(rq);
+	queue_pull_task(rq);
 }
 
 /*
@@ -1722,21 +1731,16 @@ static void switched_from_dl(struct rq *
  */
 static void switched_to_dl(struct rq *rq, struct task_struct *p)
 {
-	int check_resched = 1;
-
 	if (task_on_rq_queued(p) && rq->curr != p) {
 #ifdef CONFIG_SMP
-		if (p->nr_cpus_allowed > 1 && rq->dl.overloaded &&
-			push_dl_task(rq) && rq != task_rq(p))
-			/* Only reschedule if pushing failed */
-			check_resched = 0;
-#endif /* CONFIG_SMP */
-		if (check_resched) {
-			if (dl_task(rq->curr))
-				check_preempt_curr_dl(rq, p, 0);
-			else
-				resched_curr(rq);
-		}
+		if (p->nr_cpus_allowed > 1 && rq->dl.overloaded)
+			queue_push_tasks(rq);
+#else
+		if (dl_task(rq->curr))
+			check_preempt_curr_dl(rq, p, 0);
+		else
+			resched_curr(rq);
+#endif
 	}
 }
 
@@ -1756,15 +1760,14 @@ static void prio_changed_dl(struct rq *r
 		 * or lowering its prio, so...
 		 */
 		if (!rq->dl.overloaded)
-			pull_dl_task(rq);
+			queue_pull_task(rq);
 
 		/*
 		 * If we now have a earlier deadline task than p,
 		 * then reschedule, provided p is still on this
 		 * runqueue.
 		 */
-		if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline) &&
-		    rq->curr == p)
+		if (dl_time_before(rq->dl.earliest_dl.curr, p->dl.deadline))
 			resched_curr(rq);
 #else
 		/*



  parent reply	other threads:[~2015-06-11 12:54 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-11 12:46 [PATCH 00/18] sched: balance callbacks v4 Peter Zijlstra
2015-06-11 12:46 ` [PATCH 01/18] sched: Replace post_schedule with a balance callback list Peter Zijlstra
2015-06-11 15:32   ` Kirill Tkhai
2015-06-18 23:00   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 02/18] sched: Use replace normalize_task() with __sched_setscheduler() Peter Zijlstra
2015-06-18 23:00   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 03/18] sched: Allow balance callbacks for check_class_changed() Peter Zijlstra
2015-06-18 23:01   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 04/18] sched,rt: Remove return value from pull_rt_task() Peter Zijlstra
2015-06-18 23:01   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 05/18] sched,rt: Convert switched_{from,to}_rt() / prio_changed_rt() to balance callbacks Peter Zijlstra
2015-06-18 23:01   ` [tip:sched/hrtimers] sched, rt: Convert switched_{from, to}_rt() " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 06/18] sched,dl: Remove return value from pull_dl_task() Peter Zijlstra
2015-06-18 23:02   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` Peter Zijlstra [this message]
2015-06-18 23:02   ` [tip:sched/hrtimers] sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 08/18] hrtimer: Remove HRTIMER_STATE_MIGRATE Peter Zijlstra
2015-06-18 22:18   ` [tip:timers/core] " tip-bot for Oleg Nesterov
2015-06-11 12:46 ` [PATCH 09/18] hrtimer: Fix hrtimer_is_queued() hole Peter Zijlstra
2015-06-18 22:18   ` [tip:timers/core] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 10/18] seqcount: Rename write_seqcount_barrier() Peter Zijlstra
2015-06-18 22:19   ` [tip:timers/core] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 11/18] seqcount: Introduce raw_write_seqcount_barrier() Peter Zijlstra
2015-06-11 15:33   ` Paul E. McKenney
2015-06-11 21:45     ` Paul E. McKenney
2015-06-12  7:08       ` Peter Zijlstra
2015-06-12 18:59       ` Oleg Nesterov
2015-06-17 12:29       ` Peter Zijlstra
2015-06-17 14:57         ` Paul E. McKenney
2015-06-17 15:11           ` Peter Zijlstra
2015-06-17 15:42             ` Paul E. McKenney
2015-06-17 16:58               ` Peter Zijlstra
2015-06-17 15:49           ` Peter Zijlstra
2015-06-17 16:37             ` Paul E. McKenney
2015-06-17 17:11               ` Peter Zijlstra
2015-06-17 18:02                 ` Paul E. McKenney
2015-06-18  9:15                   ` Peter Zijlstra
2015-06-18  9:40                     ` Ingo Molnar
2015-06-18 10:40                       ` Peter Zijlstra
2015-06-18 16:54                         ` Paul E. McKenney
2015-06-18 17:10                           ` Steven Rostedt
2015-06-18 17:51                             ` Paul E. McKenney
2015-06-18 22:19         ` [tip:timers/core] seqcount: Introduce raw_write_seqcount_barrier( ) tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 12/18] hrtimer: Allow hrtimer::function() to free the timer Peter Zijlstra
2015-06-18 22:19   ` [tip:timers/core] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 13/18] sched,dl: Fix sched class hopping CBS hole Peter Zijlstra
2015-06-18 23:02   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 14/18] sched: Move code around Peter Zijlstra
2015-06-18 23:02   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 15/18] sched: Streamline the task migration locking a little Peter Zijlstra
2015-06-18 23:03   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 16/18] lockdep: Simplify lock_release() Peter Zijlstra
2015-06-18 23:03   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 17/18] lockdep: Implement lock pinning Peter Zijlstra
2015-06-18 23:03   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-06-11 12:46 ` [PATCH 18/18] sched,lockdep: Employ " Peter Zijlstra
2015-06-18 23:04   ` [tip:sched/hrtimers] " tip-bot for Peter Zijlstra
2015-12-29  5:41 ` [PATCH 00/18] sched: balance callbacks v4 Byungchul Park

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